Re: migrating from single disk to RAID 5

Paul Wehr <postgresql(at)industrialsoftworks(dot)com> writes:

> I've moved our database from a single 30G drive with reiserfs
> (3.6.25 on kernel 2.4.9) to a 4-drive RAID 5 of 80G disks with
> reiserfs on that (yeilding 167G). The performance is fantastic, but
> the backend server is periodically crashing.
>
>
> With almost no information whatsoever, anyone care to speculate on if this is:
>
> 1) hardware problem (seems unlikely since the drives are < 1 year old)
> 2) reiserfs or kernel bug

Both of the above should result in syslog entries (IDE timeouts or
parity errors, or an OOPS). Check your logs.

> 3) problem with a) shutting down postgres, b) cp -arv /olddata /newdata, c)
> edit /etc/rc.d, d) start postgres

AFIAK this should be OK.

> Not much to go on, I know, but obviously we are in big trouble if
> the database is "randomly" crashing (it seems to work fine maybe 90%
> of the time), and I'm worried about data corruption..

Make sure your PG is compiled with debugging and run with
"ulimit -c <bignum>". Next time you crash, get a backtrace from the
core file (in $PGDATA) with gdb and post it.

Oh, BTW, what version of PG is this?

-Doug
--
Let us cross over the river, and rest under the shade of the trees.
--T. J. Jackson, 1863